French presidential candidate Francois Hollande has widened his lead over his opponent, incumbent Nicolas Sarkozy, just seven weeks before the election but most voters find the campaign so far has been disappointing, a poll showed on Tuesday.

The poll by CSA showed the Socialist Hollande getting 30 percent support in the first round of a two-round election, up two percentage points, while Sarkozy gained one point to 28 percent.

In the decisive final round of voting on May 6, Hollande was seen retaining a wide lead over Sarkozy, beating him by 54 percent to 46 percent, unchanged from the previous month.

Marine Le Pen, head of the far-right National Front, fell back two percentage points to 15 percent support in the first round of voting on April 22, while far-left chief Jean-Luc Melenchon gained 1 point to 10 percent.

With the election drawing near, the poll found that a big majority of French voters were disappointed by a campaign in which nasty barbs between politicians have often drowned out debates on core policies.

CSA's poll showed that 71 percent of respondents agreed with the statement that the campaign does not allow voters to make thoughtful choices and gives too much room to exchanges between the candidates.

Half of respondents said they expected Hollande to win the election, up 11 percentage points from the previous poll, versus 30 percent for Sarkozy, down two percentage points.

The poll for BFTTV, RMC, 20 Minutes and CSC was conducted on March 5 and questioned 1,002 people.

(Reporting By Nicholas Vinocur; Editing by Tim Pearce)